Process for treating fiber-yielding materials.



UNITED STATES PATENT ()1315 10111.

QEABLES FRANK imme AND JASON LESLIE MERRILL, F wasnm'e'romnrsrarc'r OFCOLUMBIA.

rnocnss roarnne'rme FIBER-YIELDING MATERIALS.

No Drawing.

Specification of Letters Patent.

Patented 3o,1912

Application filed October 27, 1911. Serial No. 657,193. 1

(DEDICATED TO THE PUBLIC.)

' ingtongDistrict of Columbia, (whose postfeasible.

ofiice a dresses are Washington, District of Columbia, respectively)have invented a new and useful Improvement in Processes for TreatingFiber-Yielding Materials.

This application is made under the act of March 3, .1883, chapter 143(22 Stat, 625), and the invention herein described and claimed may beused by the Government of the United States or any of its ofiicers oremployees in the prosecution of work for the United States, or by anyperson in the United States, without the payment of any royalty thereon.

Our invention relates to the treatment of fiber yielding materials, suchas wood, flax, bagasse, straw, etc. s

The object of our invention is to provide a process for treatingcellulose containing materials by subjecting them to the action of achemical or chemicals in a gaseous or vaporous condition or medium atordinary or elevated temperatures or pressures, thus dispensing with thenecessity of subjecting the material to the-action of chemicals in. asolution as is done by known pressures.

Another essential object accomplished by our process is the shorteningof the time required in treating the materials. The time of treatment isreduced due to the more rapid penetration and action of chemicals ingaseous or vaporous state or medium. A further result is attained by thelessening of the smaller volume of liquid required to be'heat-. ed inthis process. I

The essential advantage of our process is in the small volume of. wasteliquor produced. In previous processes, the by-prodnets are removed inthe large volume of cooking solution used, while inour process theproducts are removed by the small volume of liquor resulting from thecondensation of the vapors. The small quantity of waste liquor producedmakes the disposal or utilization of the same .much more In practicingourprocess, the fibrous ma;

terial is out into pieces of appropriate size and then placed in' adigesting vessel ofany modern type of construction. After whichoperation the material is then subjected to the action ofgases orvapors, i. e.,-sulfur dioxid, ammonia and steam, under any suit: ablepressure, preferably from 25 lbs. to, 125 lbs., and at any suitabletemperature, preferably from 125 to 160 C. The temperature and pressurewithin the digester are regulated and controlled in the usual-manner.The gases and vapors are introduced int-o the digester for action on thematerial through pipes connected to the digester from tanks where suchgases or vapors are under pressure exceeding those maintained in thedigester, said latter pressure being obtained by the use of pumps or byliquids or solutions which evolve gases or vapors, such as an ammoniumsulfite solution. We employ free ammonia and ammoniasulfite at the sametime in carrying out the process herein disclosed.

The concentration of the chemicals in the digester are regulated andmaintained by the quantities introduced. therein either continually orintermittently ,during the process. The vapors condensed within thedigester and containing part or all of the products from the chemicalaction on the material treated may be removed therefrom eithercontinuously or at intervals by the aid of a suitable relief valveattached to the digester. After the material has been sub jected to theprocess herein described for such a period that it becomes readilydisin-. tegrated by slight mechanical action, the operation is complete,and the material is then; in condition to be removed from the .digester.

Having thus described our invention, we claim:

1. In a process for segregating fibers or. cellulose from fibrous orcellulose containing materials by subjecting the materials to the actionof ammonium sulfite, ammonia and steam ,in a gaseous state,substantially as specified.

2. In a process for segregating fibers or cellulose from fibrous orcellulose containing materials by subjecting-the materials to the actionof sulfur dioxid, ammonia and steam 3. In a process for segregatingfibers or tures in the presence of two subscribed witcellulose fromfibrous or cellulose containnesses.

ing materials by subjecting the materials to CHARLES FRANK SAMMET. theaction under pressure of sulfite dioxid, JASON LESLIE MERRILL.

5 ammonia and steam in a, gaseous state, sub- Witnesses:

stantially as specified. C. F. SPEH,

In testimony whereof We affix our signa- EDWARD O. REED.

